Question

in electric heater, why when we touch it is not conducive?   also how can only the heater heats up while the wire is cold????

Answer 1

The electric current flows through a conductor (resistance wire) and generates heat. The resistance wire is insulated from the steel Alloy Sheath with a cloth that's associate insulator for electricity however a decent conductor of heat (e.g. Mica).

The coils are thermally conductive however not electrically conductive. The electrical heating parts/elements are embedded within the coils; the aim of the coils is to tranfer heat from the electric resitance heater parts to the pot.

So once the electricity flows through the conductor/resistance wire, heat is generated and conducted to the steel surface by the thermally conductive insulation, to heat the utensil. However, even though you touch the utensil, no electrical connection will be created to the resistance wire, as a result of the presence of electrical insulator shown above. therefore you cannot get shocked!